The present invention relates to a method for extracting high levels of xcex2-glucan from a grain product such as oat or barley grain to produce a xcex2-glucan product containing at least about 18% by weight xcex2-glucan. The present invention also relates to an agglomerated food additive having at least 18% by weight xcex2-glucan and to a method of enriching a food product with xcex2-glucan using the agglomerated high content xcex2-glucan food additive.
Various sources of soluble dietary fibers have attracted much attention in recent years for their positive nutritional attributes. One such soluble dietary fiber, xcex2-glucan, is a naturally occurring polysaccharide found in the cell walls of grains such as wheat, oats and barley. When incorporated into a person""s diet, xcex2-glucan has been found to aid in the digestive process, enhance the immune system and help protect against bacteria, viruses and diseases. xcex2-glucan is known to reduce both serum cholesterol and triglyceride levels. Taken regularly, xcex2-glucan has also been found to reduce the risk of coronary heart disease.
xcex2-glucan occurs in quantity in the cell wall fibers of oats and barley grain. Despite these seemingly abundant sources, current methods to recover xcex2-glucan have been met with limited success. Known methods to isolate xcex2-glucan from its native endosperm wall are either low in yield or involve detailed chemical processes and extensive reaction times which make such processes commercially unappealing.
A need exists for an efficient process to produce a product having high concentrations of xcex2-glucan that can be commercially practiced. A need also exists for a high concentration xcex2-glucan food additive that can be readily incorporated into various types of food products with a minimum amount of work and disruption of the food product to produce a resulting food product having a suitable concentration of xcex2-glucan to achieve the desired health benefits and/or amount of fiber, particularly on a per serving basis.
Accordingly, one aspect of the present invention relates to a simple, cost-effective and commercially attractive method to produce a high concentration xcex2-glucan product from a grain product. In accordance with one aspect of the present invention, the process for preparing a high concentration xcex2-glucan product includes forming an aqueous slurry of a xcex2-glucan-containing grain product having a relatively low concentration of xcex2-glucan (typically less than 8% by weight), the slurry typically having a temperature in an operating temperature range of from about 110xc2x0 F. to about 140xc2x0 F. Thereafter, the pH of the aqueous slurry is adjusted to be in the range of from about 7.9 to about 10.0 (preferably 8.1) while maintaining the slurry in the operating temperature range. The pH-adjusted slurry is then held in the operating temperature range for at least about 50 minutes to about 120 minutes. Thereafter, the slurry is acidified to a separating pH in the range of from about 4.0 to about 4.8, preferably 4.2 to about 4.8. The acidified slurry is then separated while at the separating pH to form a xcex2-glucan rich supernatant fraction having a xcex2-glucan concentration on a dry weight basis of the supernatant of from about 18% to about 30%.
In accordance with another aspect of the process of the present invention, at least 80% of the xcex2-glucan in the grain product is extracted and recovered in the xcex2-glucan containing supernatant fraction.
In accordance with another aspect of the process of the present invention, sodium hydroxide is utilized as the base reagent and hydrochloric acid is used as the acidifying agent.
In accordance with yet another aspect of the process of the present invention, the xcex2-glucan containing supernatant fraction is separated by decantation, centrifugation and spray drying.
In accordance with another aspect of the invention, a water soluble high concentration xcex2-glucan food additive is provided. The food additive contains at least about 18% by weight xcex2-glucan. The food additive is used to increase the nutritional benefits of numerous types of food products by incorporating a desired amount of the xcex2-glucan food additive into the food product. Any suitable food product can be used in accordance with the invention, whether liquid, solid, semi-solid or semi-liquid, such as meat, cheese, fish, poultry, eggs, beverages, baked goods, beverage mixes, health bars, nutritional supplements and tablets, by way of example, but not limitation.
In accordance with another aspect of the invention, the xcex2-glucan food additive produced by the process previously described is agglomerated into particles having a size in the range of about 75 to about 840 microns (micrometers) which facilitates its use as a functional xcex2-glucan ingredient in either wet or dry food products. xcex2-glucan in such form is readily dispersable into such food products while subjecting the food product to a minimum amount of mixing and shear forces, thus minimizing disruption of the original food product.
In accordance with another aspect of the invention, the high concentration xcex2-glucan food additive is provided in tablet form so as to be ingested directly as a dietary supplement.
In accordance with another aspect of the invention, a method of making a xcex2-glucan enriched food product is provided that includes adding high concentration xcex2-glucan food additive (generally having about 18-30% by weight xcex2-glucan) derived from grain to another, different food component having no appreciable or less than a desired amount of xcex2-glucan therein. Sufficient high concentration xcex2-glucan is added to reach a desired concentration in the resulting food product. The xcex2-glucan additive is composed of agglomerated particles, the particles forming the agglomeration typically being in the size range of from about 44 mxcexc to about 150 mxcexc and the agglomerated particles being in the size range of from about 75 mxcexc to about 840 mxcexc. The agglomerated xcex2-glucan food additive is then uniformly dispersed into the food component. The other food component generally may be either solid or liquid and may be selected from a wide range of food products. The concentration of xcex2-glucan in the total food product typically is in the range of 0.1% to 20% by weight and preferably is in an amount sufficient to provide from about 0.75 to about 3.0 grams of xcex2-glucan per individual serving size of the food product.
In accordance with another aspect of the invention, a food product containing the high concentration xcex2-glucan food additive derived from a grain product is provided. The food product can be as previously described. Generally, the xcex2-glucan enriched food product has a 0.1% to 20% by weight xcex2-glucan content and preferably is uniformly dispersed within the food product.